xsltext.pxi
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# XSLT extension elements cdef class XSLTExtension: u"""Base class of an XSLT extension element. """ def execute(self, context, self_node, input_node, output_parent): u"""execute(self, context, self_node, input_node, output_parent) Execute this extension element. Subclasses must override this method. They may append elements to the `output_parent` element here, or set its text content. To this end, the `input_node` provides read-only access to the current node in the input document, and the `self_node` points to the extension element in the stylesheet. Note that the `output_parent` parameter may be `None` if there is no parent element in the current context (e.g. no content was added to the output tree yet). """ pass def apply_templates(self, _XSLTContext context not None, node, output_parent=None, *, elements_only=False, remove_blank_text=False): u"""apply_templates(self, context, node, output_parent=None, elements_only=False, remove_blank_text=False) Call this method to retrieve the result of applying templates to an element. The return value is a list of elements or text strings that were generated by the XSLT processor. If you pass ``elements_only=True``, strings will be discarded from the result list. The option ``remove_blank_text=True`` will only discard strings that consist entirely of whitespace (e.g. formatting). These options do not apply to Elements, only to bare string results. If you pass an Element as `output_parent` parameter, the result will instead be appended to the element (including attributes etc.) and the return value will be `None`. This is a safe way to generate content into the output document directly, without having to take care of special values like text or attributes. Note that the string discarding options will be ignored in this case. """ cdef xmlNode* c_parent cdef xmlNode* c_node cdef xmlNode* c_context_node assert context._xsltCtxt is not NULL, "XSLT context not initialised" c_context_node = _roNodeOf(node) #assert c_context_node.doc is context._xsltContext.node.doc, \ # "switching input documents during transformation is not currently supported" if output_parent is not None: c_parent = _nonRoNodeOf(output_parent) else: c_parent = tree.xmlNewDocNode( context._xsltCtxt.output, NULL, <unsigned char*>"fake-parent", NULL) c_node = context._xsltCtxt.insert context._xsltCtxt.insert = c_parent xslt.xsltProcessOneNode( context._xsltCtxt, c_context_node, NULL) context._xsltCtxt.insert = c_node if output_parent is not None: return None try: return self._collectXSLTResultContent( context, c_parent, elements_only, remove_blank_text) finally: # free all intermediate nodes that will not be freed by proxies tree.xmlFreeNode(c_parent) def process_children(self, _XSLTContext context not None, output_parent=None, *, elements_only=False, remove_blank_text=False): u"""process_children(self, context, output_parent=None, elements_only=False, remove_blank_text=False) Call this method to process the XSLT content of the extension element itself. The return value is a list of elements or text strings that were generated by the XSLT processor. If you pass ``elements_only=True``, strings will be discarded from the result list. The option ``remove_blank_text=True`` will only discard strings that consist entirely of whitespace (e.g. formatting). These options do not apply to Elements, only to bare string results. If you pass an Element as `output_parent` parameter, the result will instead be appended to the element (including attributes etc.) and the return value will be `None`. This is a safe way to generate content into the output document directly, without having to take care of special values like text or attributes. Note that the string discarding options will be ignored in this case. """ cdef xmlNode* c_parent cdef xslt.xsltTransformContext* c_ctxt = context._xsltCtxt cdef xmlNode* c_old_output_parent = c_ctxt.insert assert context._xsltCtxt is not NULL, "XSLT context not initialised" # output_parent node is used for adding results instead of # elements list used in apply_templates, that's easier and allows to # use attributes added to extension element with <xsl:attribute>. if output_parent is not None: c_parent = _nonRoNodeOf(output_parent) else: c_parent = tree.xmlNewDocNode( context._xsltCtxt.output, NULL, <unsigned char*>"fake-parent", NULL) c_ctxt.insert = c_parent xslt.xsltApplyOneTemplate(c_ctxt, c_ctxt.node, c_ctxt.inst.children, NULL, NULL) c_ctxt.insert = c_old_output_parent if output_parent is not None: return None try: return self._collectXSLTResultContent( context, c_parent, elements_only, remove_blank_text) finally: # free all intermediate nodes that will not be freed by proxies tree.xmlFreeNode(c_parent) cdef _collectXSLTResultContent(self, _XSLTContext context, xmlNode* c_parent, bint elements_only, bint remove_blank_text): cdef xmlNode* c_node cdef xmlNode* c_next cdef _ReadOnlyProxy proxy cdef list results = [] # or maybe _collectAttributes(c_parent, 2) ? c_node = c_parent.children while c_node is not NULL: c_next = c_node.next if c_node.type == tree.XML_TEXT_NODE: if not elements_only: s = funicode(c_node.content) if not remove_blank_text or s.strip(): results.append(s) s = None elif c_node.type == tree.XML_ELEMENT_NODE: proxy = _newReadOnlyProxy( context._extension_element_proxy, c_node) results.append(proxy) # unlink node and make sure it will be freed later on tree.xmlUnlinkNode(c_node) proxy.free_after_use() else: raise TypeError, \ f"unsupported XSLT result type: {c_node.type}" c_node = c_next return results cdef _registerXSLTExtensions(xslt.xsltTransformContext* c_ctxt, extension_dict): for ns_utf, name_utf in extension_dict: xslt.xsltRegisterExtElement( c_ctxt, _xcstr(name_utf), _xcstr(ns_utf), <xslt.xsltTransformFunction>_callExtensionElement) cdef void _callExtensionElement(xslt.xsltTransformContext* c_ctxt, xmlNode* c_context_node, xmlNode* c_inst_node, void* dummy) with gil: cdef _XSLTContext context cdef XSLTExtension extension cdef python.PyObject* dict_result cdef xmlNode* c_node cdef _ReadOnlyProxy context_node = None, self_node = None cdef object output_parent # not restricted to ro-nodes c_uri = _getNs(c_inst_node) if c_uri is NULL: # not allowed, and should never happen return if c_ctxt.xpathCtxt.userData is NULL: # just for safety, should never happen return context = <_XSLTContext>c_ctxt.xpathCtxt.userData try: try: dict_result = python.PyDict_GetItem( context._extension_elements, (c_uri, c_inst_node.name)) if dict_result is NULL: raise KeyError, f"extension element {funicode(c_inst_node.name)} not found" extension = <object>dict_result try: # build the context proxy nodes self_node = _newReadOnlyProxy(None, c_inst_node) if _isElement(c_ctxt.insert): output_parent = _newAppendOnlyProxy(self_node, c_ctxt.insert) else: # may be the document node or other stuff output_parent = _newOpaqueAppendOnlyNodeWrapper(c_ctxt.insert) if c_context_node.type in (tree.XML_DOCUMENT_NODE, tree.XML_HTML_DOCUMENT_NODE): c_node = tree.xmlDocGetRootElement(<xmlDoc*>c_context_node) if c_node is not NULL: context_node = _newReadOnlyProxy(self_node, c_node) else: context_node = None elif c_context_node.type in (tree.XML_ATTRIBUTE_NODE, tree.XML_TEXT_NODE, tree.XML_CDATA_SECTION_NODE): # this isn't easy to support using read-only # nodes, as the smart-string factory must # instantiate the parent proxy somehow... raise TypeError(f"Unsupported element type: {c_context_node.type}") else: context_node = _newReadOnlyProxy(self_node, c_context_node) # run the XSLT extension context._extension_element_proxy = self_node extension.execute(context, self_node, context_node, output_parent) finally: context._extension_element_proxy = None if self_node is not None: _freeReadOnlyProxies(self_node) except Exception as e: try: e = unicode(e).encode(u"UTF-8") except: e = repr(e).encode(u"UTF-8") message = python.PyBytes_FromFormat( "Error executing extension element '%s': %s", c_inst_node.name, _cstr(e)) xslt.xsltTransformError(c_ctxt, NULL, c_inst_node, "%s", message) context._exc._store_raised() except: # just in case message = python.PyBytes_FromFormat( "Error executing extension element '%s'", c_inst_node.name) xslt.xsltTransformError(c_ctxt, NULL, c_inst_node, "%s", message) context._exc._store_raised() except: # no Python functions here - everything can fail... xslt.xsltTransformError(c_ctxt, NULL, c_inst_node, "Error during XSLT extension element evaluation") context._exc._store_raised() finally: return # swallow any further exceptions
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